National Coral Reef Monitoring Program

Climate Monitoring Brief: St. Croix, USVI


New Subsurface Temperature Recorder deployed at White Shoal in Dry Tortugas National Park

New Subsurface Temperature Recorder deployed at White Shoal in Dry Tortugas National Park


Atlantic Oceanographic & Meteorological Laboratory Coral Program
University of Miami Cooperative Institute of Marine and Atmospheric Science
National Oceanic Atmospheric Administration


N. Besemer, A. Palacio, A. Webb, G. Kolodziej, M. Chakraborty, I. Enochs - October 2022


About this summary brief

The NOAA Atlantic Oceanographic and Meteorological Laboratory (AOML) conducts the long-term National Coral Reef Monitoring Program (NCRMP) to track the status and trends of coral reef ecosystems of the U.S. Atlantic and Caribbean coral reef jurisdictions. This FY21 summary brief provides an overview of the most recent survey efforts.

Expedition summary


Data collection

Number of temperture observations collected by transect and depht
Transect 01m 05m 15m 25m Total
east 314,505 314,508 315,351 315,345 1,259,709
north NA 313,850 313,887 257,270 885,007
south 231,351 315,094 315,095 315,091 1,176,631
west NA 314,240 314,245 314,243 942,728


Figure 1: Study sites and depths in Dry Tortugas National Park area


Temperature

Three years of temperature measurements were retrieved and processed from 14 sites (depths). Temperature was measured using SeaBird Electronics Subsurface Temperature Recorders (STR)s that collected data at 5-minute intervals.

Figure 2: Temperature conditions at four transects in Saint Croix (east, west, north and south) representing a depth gradient (1m, 5m, 15mand 25m). CHANGE THIS: Data were collected from September 2019 to September 2022. DID ANY NOT LOG THE FULL TIME?)

Temperature values were similar among the transects and depths depths with the lowest temperatures generally occurring in March (mean: 26.56 \(^\circ\)C, min: 25.64 \(^\circ\)C, max: 28.27 \(^\circ\)C) and the the highest temperatures in September(mean: 29.68 \(^\circ\)C, min: 27.22 \(^\circ\)C, max: 32.11\(^\circ\)C). The south 1m station presented the highest temperature variability and the maximum temperature values recorded in October 2021 (32.16\(^\circ\)C) and September 2020 (32.11\(^\circ\)C) (Fig. 2).


Diurnal Suite Deployment

At the North 15m site, Salt River Bay, additional instruments were deployed for a 72-hour diurnal suite that monitored pH, temperature, light and current speed (Fig. 3). The SeaFET pH logger, EcoPAR and Tiltmeter collected measurements at 15-minute intervals.

Figure 3: Salt River Bay (N 15m) diurnal suite monitoring from Sept 5th to Sept 8th. Top panel: pH and temperature from SeaFET. Bottom panel: Photosynthetically Available Radiation (PAR) and current speed from EcoPAR and Tiltmeter. Grey blocks denote night time throughout sequence of the plot. Instruments measured parameters every 5 minutes.

As part of the diurnal suite, discrete water samples were collected at three-hour intervals (n=15) using Subsurface Automatic Samplers (SAS). These samples will be analyzed for Total Alkalinity (TA), Dissolved Inorganic Carbon (DIC), and Spectrophotometric pH (SpecpH). Using these metrics we can get the calculated values for pCO2 and aragonite saturation state. For more information on SAS vist https://www.coral.noaa.gov/accrete/sas/

Submered Automated Samplers (SAS) deployed to collect water samples every 3 hours

Submered Automated Samplers (SAS) deployed to collect water samples every 3 hours


Carbonate budgets

At Salt River Bay, 6 transects were established in 2019 and surveyed to obtain carbonate budgets which quantify reef building organisms and reef eroders to determine if a reef is net growing or net eroding. (Fig. 4).We revisited this site to complete individual surveys on benthic cover, parrotfish, urchin and bioeroding sponge abundance to see if there is a change in the reef budget over 3 years.

Figure 4: EXPLAIN THIS PLOT.

Other Deliverables

  • Calcification Accretion Units (CAUs) and Bioerosion Monitoring Units (BMUs) were collected and redeployed for the next sampling cycle. CAUs are processed by the Pacific Climate group and the data will be available within a year. BMUs will be dried and cleaned using a hydrogen peroxide solution. These samples will be weighed and scanned using a Macro CT scanner and then compared to their pre-scans to quantify bioerosion. Data will be available in a year. Please reference previous datasets for more information.
CAU and BMU pair before retreval after being deployed for 3 years. CAUs are 2 parallel PVC plates to quantify settled accretors. BMU is mounted coral skeleton installed at the base of the metal stake and has been encrusted.

CAU and BMU pair before retreval after being deployed for 3 years. CAUs are 2 parallel PVC plates to quantify settled accretors. BMU is mounted coral skeleton installed at the base of the metal stake and has been encrusted.

  • Landscape mosaics (n=6) and carbonate budget surveys (n=6) were completed to monitor changes in benthic cover and carbonate production
Landscape Mosaic collected from transect 6

Landscape Mosaic collected from transect 6


About the monitoring program

AOML’s climate monitoring is a key part of the National Coral Reef Monitoring Program of NOAA’s Coral Reef Conservation Program (CRCP), providing integrated, consistent, and comparable data across U.S. Managed coral reef ecosystems. CRCP monitoring efforts aim to:

  • Document the status of reef species of ecological and economic importance.
  • Track and assess changes in reef communities in response to environmental stressors or human activities.
  • Evaluate the effectiveness of specific management strategies and identify actions for future and adaptive responses.

Point of Contact

Atlantic Climate team lead:

Principal Investigator:

NCRMP Coordinator:

For more information

Coral Reef Conservation Program: http://coralreef.noaa.gov

NCRMP climate monitoring: https://www.coris.noaa.gov/monitoring/climate.html

NOAA Atlantic Oceanographic and Meteorological Laboratory: http://www.aoml.noaa.gov/

USVI Reef Status Report 2020

National Coral Reef Status Report 2020

Acknowledgements

These efforts were jointly funded by NOAA’s CRCP and OAP. We would like to sincerely thank the National Park Service as well as Caribbean Sea Adventures for supporting our field efforts and assisting monitoring surveys

Our Team

AOMLs NCRMP Atlantic and Caribbean Climate Team: I. Enochs, N. Besemer, G. Kolodziej, M. Chakraborty, A.Boyd, M. Jankulak, A. Palacio-Castro, A. Webb, B. Chomitz